function [ zColName ] = getZColName( this, zColId )
% DataMatrix::getZColName
% Get the column names of the DataMatrix object
%
% Input
% 1. dataMatrix
% 1. zColId : sub-reference to which col names to get
%             set to ':' if not explicitly specified
%
% Output
% 1. zColName : col names of the DataMatrix object
%               ( nCol-by-1 cell )
%
% Syntax
% 1. zColName = dataMatrix.getZColName();
% 2. zColName = dataMatrix.getZColName(1:2);
% 3. zColName = dataMatrix.getZColName(':');

% Return all $zColName$ if @zColId$ is not explicitly specified
if nargin == 1
    zColId = ':';
end

zColName = this.zColName(zColId);

end
